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<HTML>
<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
</CENTER>
<HR>
<H3>compute temp/drude command
</H3>
<P><B>Syntax:</B>
</P>
<PRE>compute ID group-ID temp/drude
</PRE>
<UL><LI>ID, group-ID are documented in <A HREF = "compute.html">compute</A> command
<LI>temp/drude = style name of this compute command
</UL>
<P><B>Examples:</B>
</P>
<PRE>compute TDRUDE all temp/drude
</PRE>
<P><B>Description:</B>
</P>
<P>Define a computation that calculates the temperatures of core-Drude
pairs. This compute is designed to be used with the thermalized Drude
oscillator model. This compute is designed to be used with the
<A HREF = "tutorial_drude.html">thermalized Drude oscillator model</A>. Polarizable
models in LAMMPS are described in <A HREF = "Section_howto.html#howto_25">this
Section</A>.
</P>
<P>Drude oscillators consist of a core particle and a Drude particle
connected by a harmonic bond, and the relative motion of these Drude
oscillators is usually maintained cold by a specific thermostat that
acts on the relative motion of the core-Drude particle
pairs. Therefore, because LAMMPS considers Drude particles as normal
atoms in its default temperature compute (<A HREF = "compute_temp.html">compute
temp</A> command), the reduced temperature of the
core-Drude particle pairs is not calculated correctly.
</P>
<P>By contrast, this compute calculates the temperature of the cores
using center-of-mass velocities of the core-Drude pairs, and the
reduced temperature of the Drude particles using the relative
velocities of the Drude particles with respect to their cores.
Non-polarizable atoms are considered as cores. Their velocities
contribute to the temperature of the cores.
</P>
<P><B>Output info:</B>
</P>
<P>This compute calculates a global scalar (the temperature) and a global
vector of length 6, which can be accessed by indices 1-6, whose components
are
</P>
<OL><LI>temperature of the centers of mass (temperature units)
<LI>temperature of the dipoles (temperature units)
<LI>number of degrees of freedom of the centers of mass
<LI>number of degrees of freedom of the dipoles
<LI>kinetic energy of the centers of mass (energy units)
<LI>kinetic energy of the dipoles (energy units)
</OL>
<P>These values can be used by any command that uses global scalar or
vector values from a compute as input. See <A HREF = "Section_howto.html#howto_15">this
section</A> for an overview of LAMMPS output
options.
</P>
<P>Both the scalar value and the first two values of the vector
calculated by this compute are "intensive". The other 4 vector values
are "extensive".
</P>
<P><B>Restrictions:</B>
</P>
<P>The number of degrees of freedom contributing to the temperature is
assumed to be constant for the duration of the run unless the
<I>fix_modify</I> command sets the option <I>dynamic yes</I>.
</P>
<P><B>Related commands:</B>
</P>
<P><A HREF = "fix_drude.html">fix drude</A>, <A HREF = "fix_langevin_drude.html">fix
langevin_drude</A>, <A HREF = "fix_drude_transform.html">fix
drude/transform</A>, <A HREF = "pair_thole.html">pair_style
thole</A>, <A HREF = "compute_temp.html">compute temp</A>
</P>
<P><B>Default:</B> none
</P>
</HTML>
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